KeyError in utils (variants in region)

[legaultmarc]

>>> from gepyto.utils.variants import ensembl_variants_in_region
>>> ensembl_variants_in_region("chr16:31500328-31500330")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/legaultmarc/miniconda3/envs/env3/lib/python3.5/site-packages/gepyto/utils/variants.py", line 85, in ensembl_variants_in_region
    if len(variant["alt_alleles"]) < 2:
KeyError: 'alt_alleles'